Mislabeling
I mentioned this briefly in the original reading clearout but return today to clarify another aspect of the point. If you are having trouble engaging the other party in a discussion, a deliberate mislabel can help draw them back in by way of tempting them into a correction. You can also employ a similar move when someone is unresponsive - ask, have you given up on this project? If they intend to reengage with the project, they'll jump at this opportunity to say "no".
A positive approach to negativity
I took a couple of interesting notes about negativity within a negotiation. The general theme across those notes is that you are better off going straight at the negative, which is for a number of reasons - denying the obvious negatives in a situation adds credence to it; acknowledging and diffusing the negative helps build working relationships; open discussion of the negative helps create a safe zone for empathy.
These remind me of an incident from a Business Bro Training I attended a couple of years ago, which had a portion about conflict. I don't think I've written about this yet, but as I plan to eventually I'll keep it short for now. The main idea in the session covered how to manage and resolve conflict, which I mostly agreed with in terms of being a valuable managerial skill, but toward the end I raised my hand and pointed out that conflict sometimes represented the best opportunity for a manager to collect information that would otherwise remain out of sight. In my mind, the best approach first manages the tension of the conflict until all the information is collected, then the focus can shift to resolving the conflict. As Voss himself notes, a skilled negotiator can take a similar approach and use conflict to energize collaboration and encourage problem-solving.
The logistical argument
One way to regain control in a discussion is to ask for the logistics. This is a good tactic for those moments when you feel like the other side's good ideas are overwhelming your interests. By asking for the logistical details (how can we do that?) you may be able to wear down your opponent before they can take advantage of the moment to push for more concessions.
Human nature
Speaking of concessions, you should remember that many people feel better when they receive a concession. It may be wise to determine your single fair offer, then work your way down to it in one or two steps. (It may also help to keep this in mind when someone makes the first offer, as you can probably negotiate it down a step or two if they are using this tactic against you.)
It's also human nature to have more confidence in a highly-specific number. Rather than using round digits, throw in a few random figures - instead of $100.00, use $101.77, and so on. If this feels silly or doesn't fit the specifics of your situation, use ranges instead of exact numbers because ranges have the power to make you seem less aggressive.